Development of Q&P steels of third generation under conditions simulating a continuous annealing process, and evaluation of their weldability by the RSW process

Abstract

Quenching and partitioning, advanced high-strength steels (Q&P-AHSS), are considered as potential candidates to satisfy the current requirements of the automotive industry in terms of passenger safety. Their fabrication at industrial scale has required modifications to well-established processes and thus, obtaining this type of microstructures through easier thermal cycles represents a current challenge for steel manufacturers. Apart from their manufacturing method, their mechanical properties and weldability are equally important. In the present work, Q&P-AHSS were obtained through short-term annealing and isothermal treatments, to further investigate the effects of resistance spot welding (RSW) parameters, on nugget quality and tensile shear strength. Results show that Q&P-AHSS can be welded with success by the RSW process, meeting the required quality specified in the standard AWS D8.9 M-2012.